Ron and Sharon Worsley live near the nature preserve where the oil leak was reported. Sharon said she's been smelling oil for several days, but she thought it was the diesel that Ron uses to power his tractor. The Enquirer/Jennifer Edwards Baker

At a press conference Wednesday morning, officials from the Environmental Protection Agency said that the rain was not impacting the the cleanup; in fact, the water flow was helping the oil get to the vacuums being used to suck up the oil and contaminated water.

The oil, contaminated water and contaminated soil is all being hauled out of the area.

Cleanup is expected to take about a week. So far, 2,000 gallons of an oil/water mixture have been recovered, officials said.

Hamilton County health officials are monitoring the air in the area. If residents feel nauseated or sick they are encouraged to stay with relatives away from the spill, officials said.

Hamilton Co Health Commissioner Tim Ingram said Wednesday that Hamilton County will test private water wells in the area. Residents with concerns about the spill should call 513-946-7808.

But Ingram wanted to assure the region that public water is safe.

"We know there are concerns from folks on private water wells. About 10-15 homes," he said.sh

Officials had not yet determined what caused the 20-inch pipeline to break or how long the oil had been leaking before it was discovered late Monday.

EPA officials set up a tent overnight in the parking lot of Dravo Park. The large tent can be used for emergencies or as a mobile hospital. In addition to the EPA, Jeff Shields, a spokesman for Sunoco Logistics, which operates the pipeline for Mid-Valley Pipeline Co., was at the site on Wednesday.

Shields said he could not estimate the cost of the cleanup. But officials said Tuesday it could be steep.

Crews will need to "build a road" to get heavy machinery into the spill area, a part of the Oak Glen Nature Preserve, to vacuum up the oil and dig up contaminated soil. With rain in the forecast, a containment structure will be built to capture oil and keep it from reaching the Great Miami River, just some 500 feet away, or spreading out on the site, said Heather Lauer, a spokeswoman for the Ohio EPA.

The spill, relatively small compared to others reported in recent years -- both in the region and other parts of the country – didn't injure anyone and was contained to the spill site by Tuesday afternoon, according to state and federal EPA officials.

Crude oil discovered spilling from an underground pipeline into a stream and marshy pond in a nature preserve in Colerain Township on Monday evening will be "tricky" to clean up, U.S. Environmental Protection Agency officials said Tuesday. They estimated the volume of the spill to be around 10,000 gallons.

The spill, relatively small compared to others reported in recent years -- both in the region and other parts of the country – didn't injure anyone and was contained to the spill site by Tuesday afternoon, according to state and federal Environmental Protection Agency officials.